Hydraulic hoist



Dec. 29, 1959 v 1 E MlNTY 2,919,109

HYDRAULIC HOIST Filed OC'C. 14, 1955 2 Sheets-Sheet 1 Dec. 29, 1959 J.E. MINTY 2,919,109

HYDRAULIC HoIsT Filed Oct. 14, 1955 2 Sheets-Sheet 2 LZ2-E IZU T C/bm EMuay United States Patent O HYDRAULIC HOIST John E. Minty, Muskegon,Mich., assigner to Manning,

Maxwell & Moore, Inc., Muskegon, Mich., a corporation of New JerseyApplication October 14, 1955, Serial No. 540,398

4 Claims. (Cl. 254-167) The present invention relates to hoists ofmoderate load carrying capacity and is, more particularly, concernedwith the provision of an improved hydraulic hoist capable of efficientuse in confined quarters.

As those skilled in the hoist art are aware, there has been an everincreasing need for an eliicient, small, hoist capable of use in minimumhead room conditions. Such hoists are necessary for home as well asindustrial shops, mass production conveyor loading and unloading, andnumerous other applications where overhead clearance is very small andat the same time a relatively high lift is desired. In the prior art,hoists intended to fill this need have required reduction gearing andother similar parts of a relatively large nature which required that thehoist be suspended below the hoisting load carrying beam or othersupport in such a manner as to waste a substantial amount of theeffective lift travel of the hoist. Further, as a result of industrydemands that such hoists be extremely safe, mechanical overhaulingdevices of relatively complex construction were necessarily incorporatedin the prior art hoists. The net result of these requirements is, andhas been, a relatively expensive hoist, either man- 'ual or electricallydriven, which has required an unduly large amount of head room or,conversely, provided only a relatively short overhead lift.

The present invention provides a novel and substantially improvedhydraulic hoisting mechanism which utilizes an absolute minimum of headroom and thereby provides a maximum of lift for any given hoistinstallation. Further, the present invention utilizes no gears,sprockets, or other mechanical load transferring devices for lifting theload and is instead constructed of relatively inexpensive parts capableof simple and inexpensive replacement. Also, a hoist is provided, inaccordance with the present invention, having a simple and yet veryeffective means for preventing load-overhauling during lowering theload, thereby providing an unusually safe, simple, device.

More specifically, the present hoist comprises a hydraulic ram operablethrough a plurality of pulleys to provide a satisfactory load liftdistance from a short ram stroke. The ram is carried in a horizontalposition in a hoist frame constructed to position the ram slightly abovethe hoist supporting beam surface and at one side thereof. The ram ispreferably actuated by means of hydraulic fluid supplied from a pump andreservoir circuit carried by the housing on the other side of the beamsupport along with an electric or pneumatic motor means for driving thepump. Additionally, through appropriate 1ocation of the circuitcomponents, a hoist housing construction is provided in which allhydraulic conduits are cast'integrally in the housing and the motor,pump and reservoir units are likewise formed integrally with or housedsimply within the confines of a one-piece housing. An hydraulic valveresponsive to a positive pump pressure during hoist lowering operationis provided in the hoist raising circuit to prevent the hoist-raisingfluid from escaping during the hoist lowering or let-down operation iceunless a positive pump pressure is acting to cause lowering. This simplevalve positively prevents the load from dropping or running away duringthe load lowering operation and accordingly provides an unusually safe,trouble free, hoist structure.

It is, therefore, an object of the present invention to provide animproved and greatly simplified hoist.

' Another object of the present invention is to provide a short strokehydraulic hoist for medium loads and maximum lift distance.

Still a further object of the present invention is to provide animproved hydraulic hoist having a simple yet extremely effectiveanti-load-overhauling device therein.

Yet another object of the present invention is to provide aninexpensive, simplified, hydraulic hoist of moderate load capacity andhaving infinitely variable hoisting velocity control while utilizing aunidirectional conventional motive power source.

A feature of the present invention is the utilization of aunidirectional electric motor-driven pump with a reversing valve forproviding simplified lifting and lowering operations in a hydraulichoist.

A further feature of the present invention is the utilization of aone-piece cast housing for hoists or the like whereby hydraulic conduitsassociated therewith may be formed integrally to eliminate all hydraulicfittings and incident leakage.

Still a further feature of the invention resides in the provision of asimple reciprocating plunger valve responsive to hydraulic pressureapplied to load lowering to permit such load lowering but to preventload lowering when no positive hydraulic pressure is applied to causeload lowering. Still other and further objects and features of thepresent invention will at once become apparent to those skilled in theart from a consideration of the attached drawings wherein a preferredform of the invention is shown by way of illustration only, and wherein:

Figure l is a side elevational view of a hoist constructed in accordancewith the principles of the present invention;

Figure 2 is an end elevational View of the hoist shown in Figure l;

' Figure 3 is a cross-sectional side elevational View taken along theline lli- III of Figure 2;

Figure 4 is a cross-sectional view in plan, the line .lV-IV of Figure 3;and

Figure 5 is an end elevational view in cross section taken along theline VV of Figure 4.

As shown on the drawings:

As may be seen from a consideration of taken along the figures,

the hoist of the present invention comprises a housing M) mounted forreciprocation along a support, such as for example, an l-beam ll bymeans of a plurality of pairs of spaced rollers i2. Preferably thehousing l0 comprises a single alloy casting of high strength lightweight material such as for example aluminum but it will, of course, beapparent that any of the stronger, though heavier, metals such as caststeel or the like may be utilized if desired. As shown, this housing isgenerally U-shaped in cross section and one leg thereof, hereinafterdesignated the left leg or bank lita `carries the hoisting ram apparatuswhile the right leg hereinafter termed the right leg or bank lilbcarries the motivating component.

As shown, the left bank 10a carries rigidly mounted thereto, a powercylinder 13 having a longitudinally extending bore 114i. A ram l5 isslidably mounted through end cap 16 of the cylinder ll3 and carries apiston 17 having an external diameter cooperating with the bore i4. Theram 15 is provided with a yoke V18 carrying a transverse shaft 19 uponwhich a plurality the housing opposite from the sheaves 20, a secondtransverse shaft 21 is mounted for the pivotal support of a plurality ofsheaves 22. Asingle strand of conventional wire rope is secured at oneend tothe housing 10 as at 23 and is successively passed about thesheaves 20 and 22, finally leaving the lowermost sheave 22a and passingto an 4idler sheave 24 and thence to the guide sheave 25 by which it isdirected into a Vertical load lifting condition. Where an integral,one-piece, cast housing is provided, it is preferably slotted out of theaperture 'cast in the frame as at 26 to permit passage of the rope 27and is recessed as at 28 to provide for reception of the sheave 24 andas at 29 for the reception of the guide sheave or pulley 25.

It will be understood that various numbers of sheaves 2t) and 22 maybeprovided, depending upon the amount of lift desired `and the strokeofthe ram kconsidered practicable. For a relatively small, medium dutyhoist, a nine inch stroke of the ram 15 with eight sheaves 20 and 22provides a twelve foot lift. This amountof lift is ordinarily ample forsmall machine shop practice and the relatively small stroke of the ram15 permits construction of the entire hoist in a relatively smallhousing l0.

`As may be seen from a consideration ofjFigures 1 and 5, the housing It)may be castor machinedwith a channel 30 with the upper and lower walls30aand 30h,

4 pressure may build up in the hoist cylinder. At the same time thateither of the cylinder conduits 57 or 58 is pressurized, the other isvented to the relief passage 55 by means of a port 6i) which leads to arelief port 61 connected to the conduit S5 through a passage 62extending longitudinally of the valve bore. The relief passage 55 leadsdirectly to a storage reservoir 63 from which oil proceeds to the pump49 via conduit 64.

As may be seen from a consideration of Figure 5, the cylinder conduit 57p-asses through the housing 10a in the fi rm of a transverse conduit 65and, when Vunder pressure, unseats a check Valve 66 to apply pressureagainst the rarn piston 17 to cause lifting movement of the rope 27.During such operation, the conduit 58 and its corresponding transverseconduit 67 are relieved of pressure through the port 60 and accordinglythe piston vl' is unlocked and free to move. Upon lowering operi ation,however, the check valve 66 will close and uid respectively, machined toprovide guide surfaces forthe yoke 1S, at the left hand end as viewed inFigure 1 and as a support for the sheaves 22, through spacers 31 at theright hand end as viewed in Figure l. While it is, of course, possibleto core the cast housing 10 to provide an integral cylinder 13, in theinterests of simplicity, the cylinder 13 may be constructed separatelyand secured in place by a plurality of cap screws 32 which may be passedthrough the openings 33 in the upper channel wall a during assembly.Construction of the cylinder 13. asa separate part permits drilling ofthe bores 34 for the reception of the stub axles 35 of the supportrollers 12.

Motive uid under pressure, for actuating the ram Y15 through piston 17is provided on the right bank 10b. The general arrangement is shown indetail in Figure 3 where a longitudinally extending bore 4l) contains aunidirectional electric motor armature 41 and eld 42. In order tosimplify mounting, and to reduce cost, the field 42 may be securedrigidly to an end plate 43 which is in turn secured to the housing i0 bymeans of fasteners 44. The armature 4l is rotatably supported as at 45in the p-late 43 and in the housing 10 by means of a bearing 46 securedby a retainer 47.

The motor armature 41 is rigidly secured to an output driveshaft 43which in turn drives a relatively high pressure oil pump hereinillustrated as a gear pump 49, through a gear connection 5t?. The pump49 may, of course, comprise any one of a number of different types ofoil pumps and the gear type pump is shown as merely one satisfactoryexample. As in the case of the motor installation, the recesses for thegear elements of the pump 49 may be cored and machined directly in thehousing I@ and closed oi by a cover plate 51 to provide an integratedunit.

High pressure oil from the pump 49 is fed to a control valve generallyindicated at 52 by means of a conduit 53. The control valve 52 maycomprise any conventional reversing valve and is here illustrated ascomprising a valve core 52a having a pressure port 54 which directs theoutput of the pump 49 to -a relief conduit 55 when the valve is inneutral position, as shown in Figure 3. When the valve is moved in thecounterclockwise direction uid under pressure is directed through boreS6 to power ycylinder conduit 57 and when rotated in the clockwisedirection the port 54 is aligned with the cylinder conduit 58. Movementaway from the neutral position will in each case cause a closing of therelief bore 59 so that trapped between-the piston 17 and the right handend of the cylinder as viewed in Figure l'may only pass back to thereservoir by means of a valve 68. The valve 68, which is shown in Figurel, comprises a reciprocable core movable into the open position upon theapplication of fluid pressure to a longitudinally extending conduit 69which is in hydraulic connection with conduits 58 and 67.V Accordingly,when pressure is applied to the conduits 58 and 67 to positively lowerthe load, the valve 68 is moved to the right as viewed in Figure l toopen a uid path to the conduit 65, thereby unlocking the ram piston 17.However, if any attempt is made by the load to overrun the force tendingto lower the load, the pressure would tend to drop in the conduit 69 andthe valve 68 will accordingly' close and prevent right hand movement ofthe piston 17. Thus, an effective loadoverhauling preventive device isincorporated in the system. r

As illustrated in the drawings, all of the necessary hydraulic conduitsmay be integrally bored in the housing 10 and accordingly the onlypossibilities for leakage occur at the Various closure plugs 70. Theseplugs are a conventional type taper plug and when properly fitted willcause absolutely no maintenance problem. Accordingly, leakage of thehydraulic system ordinarily encountered in hydraulic devices havingexternally mounted conduits, is completely eliminated in the instanthoist apparatus.v Further, by coring or drilling the housing 10 toprovide for not only the motor 41 but also the pump 49,`the valve 52 andthe reservoir 63, an extremely inexpensive and strong system isprovided.

In operation, the valve core 52 Vmay be rotated by means of an extendingvalve stem 71 connected to a rope operated rocker arm 72 for manualoperation from below. Preferably, a push button switch of anyconventional design is attached to the control rope leading from therocker arm 72 for purposes of energizing the motor when the hoist is tobe placedA in operation. In view of the reversing nature of the valve,however, it will be understood that the motor may be left runningconstantly during operation ofV the hoist and that all control of thehoist may be accomplished, insofar as lifting and lowering is concerned,through actuation of the valve 52. Innitely variable speed control isprovided for the hoist lifting by the valve 52 since the relief port 55is gradually closed off with rotation of the valve control stem 71. Thisgradual closing permits a gradual build-up and complete control of thepressure -applied to the cylinder conduits 57 and 58 and accordingly theload may be lifted very vgradually even though it is low in weight. Itwill be apparent, of course, to those skilled inv the art that theutilization of the most inexpensive type of unidirectional electricmotor is per missible with the present hoist since the motor iscornpletely independent of the lifting parts. Thus, the motor need notonly not have reversibility but'its inertia characteristic, or abilityto stop and start in short spaces Y s of time, is in no sense critical.This is an important advantage over prior art hoist structures in whichexpensive electrical components have been considered essential tosatisfactory operation.

As above described, the load-overhauling preventing valve 68 willprevent dropping of the load under all circumstances. This is animportant safety feature but it is recognized that in some instances itmay be desirable to lower the load during a power failure or othercircumstances which would make it impossible to apply pressure to thevalve control conduit 69. Accordingly, the valve core 68 which isordinarily spring biased into valve closed position by a spring 73, maybe manually moved into the valve-open position by means of a knob 74which may be appropriately indicated to be an emergency loweringcontrol.

It will thus be seen that I have provided a novel hoist capable ofoperation with an overhead supporting beam, such as for example anI-beam, which requires substantially no head room and which providesutmost strength with a minimum of manufacturing cost.

While it will be apparent that the component parts may be varied as todimension and power, it has been found that a very satisfactory moderateload may be provided where the motor 41 comprises a one-half horsepower1800 r.p.m. motor driving the gear pump 49 to provide an oil pressuremaximum of 1500 pounds per square inch. Using these components, a fairlywide range of load capacities may be provided merely by changing thediameter of the piston 17. With a piston diameter of four inches,however, and utilizing a maximum hydraulic pump outlet pressure of 1500pounds per square inch with a 16 to l lift-to-stroke ratio, a loadcapacity of over 1000 pounds may readily be provided.

While not shown in the drawings it will be understood that the hoist ofthe present invention may be powered to move the housing along the rail11 in a simple manner. For example, any one or more of the rollers 12may be actuated by a reversible hydraulic motor deriving its source ofpower from hydraulic conduit S3 through a conventional reversing valveunder manual control. For example, the roller 12 shown in the lower lefthand corner of the housing 10 in Figure 4 may be driven by a hydraulicmotor controlled by a second valve positioned beside the valve 52 andcontrolling the uid from the high pressure conduit 53. Rotation of theroller 12 will, of course, cause the housing 10, with the load carriedthereby, to move along the rail 11 to any position desired and thisadditional power may accordingly be found desirable where the hoist isto be used with large, ungainly objects or the like.

It will, of course, be understood that still further variations andmodifications may be made in accordance with the principles of thepresent invention without departing from the scope of the novel conceptsthereof. Accordingly, it is my intention that the scope of the presentinvention be limited solely by that of the hereinafter appended claims.

I claim as my invention:

1. A unitary hoist apparatus comprising a one-piece housing having anupwardly opening channel extending longitudinally therealong, ahydraulic hoisting ram secured to said housing on one side of saidchannel and extending longitudinally therealong, said rarn comprising areciprocal piston rod carrying sheave means, sheave means on saidhousing and a hoisting cable trained about said sheave means for liftingmovement when said piston rod is extended, a cable guide in said housingimmediately under said channel and guide means directing said cable fromsaid sheave means to said cable guide to thereby direct said hoistingcable downwardly in a substantially vertical direction from the samepoint at all times immediately under said housing means, hydraulic meanson the other side of said channel for reciproeating said ram duringhoisting operations, said hydraulic means comprising a pump, a reversingvalve anda hydraulic fluid reservoir all integrally housed in saidhousing, motor means for driving said pump, and a pair of hydraulicconduits beneath said channel and connecting said valve with oppositesides of said ram to control reciprocation of said piston rod, saidconduits comprising the sole drive connection between opposite sides ofsaid channels.

2. A hydraulic hoist comprising a housing having a centrally mountedsupport means for maintaining said hoist in an overhead position, asubstantially horizontally disposed hydraulic ram positioned on one sideof said support means, said ram comprising a reciprocal piston rodcarrying a plurality of rotatable sheaves, a second group of rotatablesheaves mounted about a fixed pivot on said housing, said pivotcomprising an -axis lying transverse and substantially normal to theaxis of reciprocation of said rod, rope means trained about said sheavesand having one end secured to said housing and the other end trainedover a sheave discharging said end in a substantially vertical directionimmediately under said support means, hydraulic fluid pressure sourcemeans positioned on the side of said support means opposite from saidram and a pair of hydraulic conduits connecting said source means tosaid ram transversely of said support means for reciprocation thereof inopposite directions, and interlock means between said pair of conduitsfor preventing reverse ow through the one thereof applying a liftingforce to said ram unless a positive pressure is applied to the othertending to lower the ram.

3. A hydraulic hoist comprising a housinghaving a centrally mountedsupport means for maintaining said hoist in an overhead position, asubstantially horizontally disposed hydraulic ram positioned on onesideof said support means, said ram comprising a reciprocal piston rodcarrying a pluralityk of rotatable sheaves, a second group of rotatablesheaves mounted about a xed pivot on said housing, said pivot comprisingan axis lying transverse and substantially normal to the axis ofreciprocation of said rod, rope means trained about said sheaves andhaving one end secured to said housing and the other end trained over asheave discharging said end in a substantially vertical directionimmediately under said support means, and hydraulic uid pressure sourcemeans positioned on the side of said support means opposite from saidram, and a pair of conduits connecting said source means to said ram forreciprocation thereof, said source of iluid under pressure comprising afluid pump, a valve, a uid reservoir, and a motor for driving said pump,said motor, pump, valve, conduits, and reservoir each having the housingthereof formed integrally with said hoist housing.

4. A hydraulic hoist comprising a housing having a centrally mountedsupport means for maintaining said hoist in an overhead position, asubstantially horizontally disposed hydraulic ram positioned'on one sideof said support means, said ram comprising a reciprocal piston rodcarrying a plurality of rotatable sheaves, a second group of rotatablesheaves mounted about a fixed pivot on said housing, said pivotcomprising an axis lying transverse and substantially normal to the axisof reciprocation of said rod, rope means trained about said sheaves andhaving one end secured to said housing and the other end trained over asheave discharging said end in a substantially Vertical directionimmediately under said support means, and hydraulic uid pressure sourcemeans positioned on the side of said support means opposite from saidram and connected to said ram for reciprocation thereof, said source offluid under pressure comprising a fluid pump, a valve, a fluidreservoir, and a motor for driving said pump, said motor, pump, valve,and reservoir each having the housing thereof formed integrally withsaid hoist housing, and said pump comprising a rotary gear pump having apair of meshed gears rotatably mounted in overlapping cylindrical boresin said hoist housing, and a cover plate secured over said bores toprovide lim enclosed Vpump housing.

References Cited in the file of` thislpatent UNITED STATES PATENTSHagenbucher June 27, 1916

